And now, air-conditioning by water

To cut down solar radiation and air conditioning costs by 90 per cent you now have structure cooling. It can help maintain an ambient temperature in any building — be it a commercial complex, a warehouse, an airport or a multi-storeyed apartment in a gated community.

Interestingly, this innovative solution draws inspiration from the past. Visitors to the Lotus Mahal palace of the Vijayanagara empire in Hampi, Karnataka, may have observed how water drawn from wells and ponds was circulated through channels to keep the buildings cool.

In a modern-day building, one can reuse treated wastewater, or source water from a lake or borewell and circulate it through pipes to lower the inside temperature. In winter, hot water can be substituted to warm the insides. The specialised pipes, now being imported, are embedded in the floor and the ceiling, and connected to a water source.

Structure cooling is now available in India. Hyderabad-based Oorja Cleantech LLP offers cooling and heating solutions for industries and commercial complexes — new and retrofits — by addressing the source of the heat.

A building accumulates heat during summer and cold during winter. Structure cooling can lower temperatures to 26-30 degrees C, with minimal load on the AC. The cost of installation in a new building is ₹100-150 per sq ft.

Says Oorja’s founder and MD, Madhusudhan Rao, “Heating and cooling are very energy-intensive processes and Oorja’s solutions either eliminate or greatly reduce the need for fossil fuel… the process also improves indoor air quality and reduces airborne diseases and the Sick Building Syndrome.” He adds that in Toronto, Canada, the local municipality uses lake water for the cooling and warming process. The low-energy cooling can cut power consumption.

“We plan to set up a plant for pipes once volumes go up,” says Rao. The company has worked on 40-plus domestic projects including at IIM Raipur, VIT Vellore, in Neyveli and in Leh.